The present invention relates to a golf ball which uses an inorganic pigment having photochromism. More particularly, the invention relates to a golf ball which exhibits a reversible change in color between exposure to a light source having a spectral distribution with a peak at the same wavelength as the absorption peak of the inorganic pigment in the visible light spectrum and exposure to another light source, and thus has excellent visibility and fashionability.
Up until now, golf balls have been predominantly white in color. Recently, however, as the range of individuals playing golf has grown, highly fashionable golf balls targeted at beginners or women are being created.
For example, published U.S. Patent Application No. 2004/0266553 discloses a golf ball which exhibits a color change under ultraviolet irradiation. However, because the pigment used in this golf ball is an organic compound, there are problems with the reversibility and life of the color change.
Published U.S. Patent Application No. 2004/0266554 uses a photoluminescent pigment, but the cost rises on account of encapsulation. Moreover, the pigment is a phosphorescent pigment, and so the speed of the color change response to visible light irradiation is slow. Also, the influence of temperature on the brightness of luminescence and the color in the luminous time period cannot be disregarded.
In addition, JP No. 3363818 discloses art relating to a reversibly color changeable composition. However, no specific means is described for conferring fashionability while maintaining properties such as flight characteristics, feel on impact and durability when this art is applied to golf balls.